A successful chemical synthesis—in both inorganic and organic chemistry—requires strict adherence to numerous reaction conditions. For example, the temperature, the concentration of the reactants, their retention time and hence the reaction time in the reactor, the pressure and the medium in which the reaction is to take place, have to be optimized in order to obtain the highest possible yield, while also taking into consideration their cost-effectiveness. The reaction mixture must almost always be post-processed for purifying the reaction products. If the individual processing steps are performed in a stationary reactor system, then a number of processing steps are required during the synthesis which typically have to be carried out manually, which is time-consuming and requires additional personnel. Stationary or semi-stationary syntheses (in batch or semi-batch reactors) have the disadvantage that the operating parameters derived from a known system cannot always be applied to a larger starting batch. The larger starting batch must frequently be optimized from the start, for example, due to problems associated with dissipation of the reaction heat. One solution is provided by so-called continuous synthesis processes, where the reactants are introduced into a transportable medium, where they react with each other, with a product being withdrawn at another location—optionally after additional processing steps. Such systems have so far been mainly employed in large-scale industrial operations that produce basic chemical materials.
The starting batches in laboratory-scale experiments or in the production of special pharmaceutical products are mostly too small to perform the syntheses common in large plants. During the past years, micro-reactor systems have been developed that advantageously employ a continuous process flow, while being configured for a much smaller total throughput. The micro-reactors offer a defined reaction space which frequently includes additional structural elements that affect the reaction conditions. For example, EP 1 031 375 A2 discloses a micro-reactor for carrying out chemical reactions that has individual, freely exchangeable micro-structured elements. Micro-reactors of the aforedescribed type can advantageously carry out process syntheses under continuous synthesis conditions, which thus far have been known only from large-scale facilities. The thermal aspect of the reaction can be controlled with hitherto unmatched precision, because the walls between the passageways transporting the reaction medium and a heat exchange medium can frequently be made very thin. The small volumes, where very small material quantities can react with each other, allow a very safe process control, in particular when carrying out critical or dangerous syntheses.
Such micro-reactors have in common that they can consist of individual processing modules designed for different tasks. The processing modules provide defined reaction spaces where the reactants are mixed and react with each other by thermal initiation or control. Additional processing modules retain the reaction medium and allow post-processing by, for example, extraction, phase separation or annealing. The individual processing modules must be in fluid communication with each other.
A micro-reactor system is described in WO 95/26796 to Bard et al., which is based on the aforedescribed modular concept. The individual processing modules are mounted on the side of a support structure. The support structure includes small channels that provide a fluid connection between the individual processing modules of the micro-reactor. For example, a reactor module, a separation module and an analyzer module are sequentially arranged on the support structure. The connecting channels of the disclosed micro-reactor system are disadvantageously fixedly integrated in the support structure, representing a fixed connection system. This limits the flexibility of the micro-reactor system which hence cannot be adapted to the often different requirements of the chemical synthesis.
Ehrfeld et al. (WO 00/62018) describe a micro-reactor system that is composed of individual processing modules. The individual processing modules are provided with connecting elements via a connection system. The connecting elements are non-positively connected during assembly in such a way that fluid channels leading from one processing module to the next are connected with each other so as to form a seal to the outside. Connecting elements are considered to be formfittingly connected when they represent an integral part of the modules. A distinction is made between formfitting and non-positive connections. With the first type of connections, the force is transmitted as a result of their form or shape, whereas with the latter type of connections, the force is transmitted through friction forces (K. H. Decker: “Machine Elements—Design and Computation), 10th printing, Carl Hanser Verlag, Vienna, 1990, p. 212). This publication does not suggest the integration of sensors and actuators in the system which is required for regulation and control.